Laundry treating appliances and methods of controlling the same to balance small loads

ABSTRACT

Laundry treating appliances and methods of controlling the same to balance small loads are disclosed. An example method of operating a laundry treating appliance having a rotating drum defining a treating chamber in which laundry is received for treatment according to at least one cycle of operation, and at least one balancing ring to counteract an imbalance of the rotating drum includes determining whether a small load is present in the treating chamber, substantially aligning the small load and a moveable mass of the balancing ring(s) when the drum is substantially stationary, and accelerating rotation of the drum based on a viscosity of fluid in the balancing ring(s) to position the small load substantially opposite the moveable mass.

FIELD OF THE DISCLOSURE

This disclosure relates generally to laundry treating appliances, and, more particularly, to laundry treating appliances and methods of controlling the same to balance small loads.

BACKGROUND

Laundry treating appliances, such as clothes washers, dryers, combination washer-dryers, refreshers, and non-aqueous systems, may have a configuration based on a rotating drum that defines a treating chamber in which laundry items are placed for treating. The laundry treating appliance may have a controller that implements a number of pre-programmed cycles of operation having one or more operating parameters. The controller may control a motor to rotate the drum according to one of the pre-programmed cycles of operation. The controller may control the motor to rotate the drum at the same speeds for a given pre-programmed cycle of operation regardless of the characteristics of the laundry items or changes in the system.

SUMMARY

A disclosed example method of operating a laundry treating appliance having a rotating drum defining a treating chamber in which laundry is received for treatment according to at least one cycle of operation, and at least one balancing ring to counteract an imbalance of the rotating drum includes determining whether a small load is present in the treating chamber, substantially aligning the small load and a moveable mass of the balancing ring(s) when the drum is substantially stationary, and accelerating rotation of the drum based on a viscosity of fluid in the balancing ring(s) to position the small load substantially opposite the moveable mass.

Another disclosed example method of operating a laundry treating appliance having a rotating drum defining a treating chamber in which laundry is received for treatment according to at least one cycle of operation, and a balancing ring to counteract an imbalance of the rotating drum includes determining a position of a moveable mass of the balancing ring, and accelerating rotation of the drum based on a viscosity of fluid in the balancing ring, a location of a small load in the treating chamber, and the detected position to position the small load substantially opposite the moveable mass at and above a critical rotation speed of the drum.

A disclosed example laundry treating appliance includes a rotating drum defining a treating chamber in which laundry is received for treatment according to at least one cycle of operation, a balancing ring coupled with the rotating drum to counteract an imbalance of the rotating drum, and a controller configured to determine whether a small load is present in the treating chamber, substantially align the small load and a moveable mass of the balancing ring when the rotating drum is substantially stationary, and accelerate rotation of the drum based on an estimated temperature of fluid in the balancing ring to position the small load substantially opposite the moveable mass at and above a critical rotation speed of the drum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an example laundry treating appliance in the form of a washing machine.

FIG. 2 is a schematic of an example control system for the laundry treating appliance of FIG. 1.

FIGS. 3-6 are flow charts illustrating example methods of balancing a small load for the washing machine of FIG. 1.

FIGS. 7A and 7B are graphs illustrating example drum acceleration ramp profiles.

FIGS. 8 and 9 are diagrams illustrating an example operation of the example laundry treating appliance of FIG. 1.

DETAILED DESCRIPTION

When small loads of laundry (e.g., one item of clothing) are washed it may be difficult for a laundry treating appliance to sufficiently balance the load in order to reach the high speed of rotation necessary to extract fluid from the laundry to a desired extent. Such circumstances may result in a longer spin cycle and/or excessively wet clothes that require an extended drying time—both of which may lead to customer dissatisfaction. To improve fluid extraction performance, laundry treating appliances and methods of controlling the same to balance small loads are disclosed herein.

FIG. 1 is a schematic view of an example laundry treating appliance. The laundry treating appliance may be any appliance that performs a cycle of operation to clean or otherwise treat items placed therein, non-limiting examples of which include a horizontal or vertical axis clothes washer; a dryer, a combination washing machine and dryer; a tumbling or stationary refreshing/revitalizing machine; an extractor; a non-aqueous washing apparatus; and a revitalizing machine.

The laundry treating appliance of FIG. 1 is illustrated as a washing machine 10, which may include a structural support system comprising a cabinet 12 that defines a housing within which a laundry holding system resides. The cabinet 12 may be a housing having a chassis and/or a frame defining an interior enclosing components typically found in a conventional washing machine, such as motors, pumps, fluid lines, controls, sensors, transducers, and the like. Such components will not be described further herein except as necessary for a complete understanding of this disclosure.

The laundry holding system typically comprises a tub 14 supported within the cabinet 12 by a suitable suspension system and a drum 16 provided within the tub 14, the drum 16 defining at least a portion of a laundry treating chamber 18. The drum 16 may include a plurality of perforations 20 such that liquid may flow between the tub 14 and the drum 16 through the perforations 20. A plurality of baffles 22 may be disposed on an inner surface of the drum 16 to lift the laundry load received in the treating chamber 18 while the drum 16 rotates. It is also within the scope of this disclosure for the laundry holding system to not include the drum 16 such that the tub 14 defines the laundry treating chamber.

The laundry holding system may further include a door 24 that may be movably mounted to the cabinet 12 to selectively close both the tub 14 and the drum 16. A bellows 26 may couple an open face of the tub 14 with the cabinet 12, with the door 24 sealing against the bellows 26 when the door 24 closes the tub 14.

The washing machine 10 may further include a suspension system 28 for dynamically suspending the laundry holding system within the structural support system.

The washing machine 10 may also include at least one balancing ring 38 containing a balancing material (i.e., mass) moveable within the balancing ring 38 to counterbalance an imbalance that may be caused by laundry in the treating chamber 18 during rotation of the drum 16. The balancing material may be in the form of metal balls or any other readily moveable mass, fluid, or a combination thereof. For example, the balancing ring 38 may be a ball balancing ring comprises a plurality of metal balls suspended in a viscous fluid. The balancing ring 38 may extend circumferentially around a periphery of the drum 16 and may be located at any desired location along an axis of rotation of the drum 16. When multiple balancing rings 38 are present, they may be spaced along the axis of rotation of the drum 16. For example, the balancing rings 38 may be equally and/or symmetrically spaced.

The washing machine 10 may further include a liquid supply system for supplying water to the washing machine 10 for use in treating laundry during a cycle of operation. The liquid supply system may include a source of water, such as a household water supply 40, which may include separate valves 42 and 44 for controlling the flow of hot and cold water, respectively. Water may be supplied through an inlet conduit 46 directly to the tub 14 by controlling first and second diverter mechanisms 48 and 50, respectively. The diverter mechanisms 48, 50 may be a diverter valve having two outlets such that the diverter mechanisms 48, 50 may selectively direct a flow of liquid to one or both of two flow paths. Water from the household water supply 40 may flow through the inlet conduit 46 to the first diverter mechanism 48, which may direct the flow of liquid to a supply conduit 52. The second diverter mechanism 50 on the supply conduit 52 may direct the flow of liquid to a tub outlet conduit 54, which may be provided with a spray nozzle 56 configured to spray the flow of liquid into the tub 14. In this manner, water from the household water supply 40 may be supplied directly to the tub 14.

The washing machine 10 may also be provided with a dispensing system for dispensing treating chemistry to the treating chamber 18 for use in treating the laundry according to a cycle of operation. The dispensing system may include a dispenser 62, which may be a single use dispenser, a bulk dispenser or a combination of a single and bulk dispenser. Non-limiting examples of suitable dispensers are disclosed in U.S. Pub. No. 2010/0000022 to Hendrickson et al., filed Jul. 1, 2008, entitled “Household Cleaning Appliance with a Dispensing System Operable Between a Single Use Dispensing System and a Bulk Dispensing System,” U.S. Pub. No. 2010/0000024 to Hendrickson et al., filed Jul. 1, 2008, entitled “Apparatus and Method for Controlling Laundering Cycle by Sensing Wash Aid Concentration,” U.S. Pub. No. 2010/0000573 to Hendrickson et al., filed Jul. 1, 2008, entitled “Apparatus and Method for Controlling Concentration of Wash Aid in Wash Liquid,” U.S. Pub. No. 2010/0000581 to Doyle et al., filed Jul. 1, 2008, entitled “Water Flow Paths in a Household Cleaning Appliance with Single Use and Bulk Dispensing,” U.S. Pub. No. 2010/0000264 to Luckman et al., filed Jul. 1, 2008, entitled “Method for Converting a Household Cleaning Appliance with a Non-Bulk Dispensing System to a Household Cleaning Appliance with a Bulk Dispensing System,” U.S. Pub. No. 2010/0000586 to Hendrickson, filed Jun. 23, 2009, entitled “Household Cleaning Appliance with a Single Water Flow Path for Both Non-Bulk and Bulk Dispensing,” and application Ser. No. 13/093,132, filed Apr. 25, 2011, entitled “Method and Apparatus for Dispensing Treating Chemistry in a Laundry Treating Appliance,” which are herein incorporated by reference in full.

Regardless of the type of dispenser used, the dispenser 62 may be configured to dispense a treating chemistry directly to the tub 14 or mixed with water from the liquid supply system through a dispensing outlet conduit 64. The dispensing outlet conduit 64 may include a dispensing nozzle 66 configured to dispense the treating chemistry into the tub 14 in a desired pattern and under a desired amount of pressure. For example, the dispensing nozzle 66 may be configured to dispense a flow or stream of treating chemistry into the tub 14 by gravity, i.e. a non-pressurized stream. Water may be supplied to the dispenser 62 from the supply conduit 52 by directing the diverter mechanism 50 to direct the flow of water to a dispensing supply conduit 68.

Non-limiting examples of treating chemistries that may be dispensed by the dispensing system during a cycle of operation include one or more of the following: water, enzymes, fragrances, stiffness/sizing agents, wrinkle releasers/reducers, softeners, antistatic or electrostatic agents, stain repellants, water repellants, energy reduction/extraction aids, antibacterial agents, medicinal agents, vitamins, moisturizers, shrinkage inhibitors, and color fidelity agents, and combinations thereof.

The washing machine 10 may also include a recirculation and drain system for recirculating liquid within the laundry holding system and draining liquid from the washing machine 10. Liquid supplied to the tub 14 through tub outlet conduit 54 and/or the dispensing supply conduit 68 typically enters a space between the tub 14 and the drum 16 and may flow by gravity to a sump 70 formed in part by a lower portion of the tub 14. The sump 70 may also be formed by a sump conduit 72 that may fluidly couple the lower portion of the tub 14 to a pump 74. The pump 74 may direct liquid to a drain conduit 76, which may drain the liquid from the washing machine 10, or to a recirculation conduit 78, which may terminate at a recirculation inlet 80. The recirculation inlet 80 may direct the liquid from the recirculation conduit 78 into the drum 16. The recirculation inlet 80 may introduce the liquid into the drum 16 in any suitable manner, such as by spraying, dripping, or providing a steady flow of liquid. In this manner, liquid provided to the tub 14, with or without treating chemistry may be recirculated into the treating chamber 18 for treating the laundry within.

The liquid supply and/or recirculation and drain system may be provided with a heating system that may include one or more devices for heating laundry and/or liquid supplied to the tub 14, such as a steam generator 82 and/or a sump heater 84. Liquid from the household water supply 40 may be provided to the steam generator 82 through the inlet conduit 46 by controlling the first diverter mechanism 48 to direct the flow of liquid to a steam supply conduit 86. Steam generated by the steam generator 82 may be supplied to the tub 14 through a steam outlet conduit 87. The steam generator 82 may be any suitable type of steam generator such as a flow through steam generator or a tank-type steam generator. Alternatively, the sump heater 84 may be used to generate steam in place of or in addition to the steam generator 82. In addition or alternatively to generating steam, the steam generator 82 and/or sump heater 84 may be used to heat the laundry and/or liquid within the tub 14 as part of a cycle of operation.

Additionally, the liquid supply and recirculation and drain system may differ from the configuration shown in FIG. 1, such as by inclusion of other valves, conduits, treating chemistry dispensers, sensors, such as water level sensors and temperature sensors, and the like, to control the flow of liquid through the washing machine 10 and for the introduction of more than one type of treating chemistry.

The washing machine 10 also includes a drive system for rotating the drum 16 within the tub 14. The drive system may include a motor 88, which may be directly coupled with the drum 16 through a drive shaft 90 to rotate the drum 14 about a rotational axis during a cycle of operation. The motor 88 may be a brushless permanent magnet (BPM) motor having a stator 92 and a rotor 94. Alternately, the motor 88 may be coupled to the drum 16 through a belt and a drive shaft to rotate the drum 16, as is known in the art. Other motors, such as an induction motor or a permanent split capacitor (PSC) motor, may also be used. The motor 88 may rotate the drum 16 at various speeds in either rotational direction.

The washing machine 10 also includes a control system for controlling the operation of the washing machine 10 to implement one or more cycles of operation. The control system may include a controller 96 located within the cabinet 12 and a user interface 98 that is operably coupled with the controller 96. The user interface 98 may include one or more knobs, dials, switches, displays, touch screens and the like for communicating with the user, such as to receive input and provide output. The user may enter different types of information including, without limitation, cycle selection and cycle parameters, such as cycle options.

The controller 96 may include the machine controller and any additional controllers provided for controlling any of the components of the washing machine 10. For example, the controller 96 may include the machine controller and a motor controller. Many known types of controllers may be used for the controller 96. The specific type of controller is not germane to this disclosure. It is contemplated that the controller is a microprocessor-based controller that implements control software and sends/receives one or more electrical signals to/from each of the various working components to affect the control software. As an example, proportional control (P), proportional integral control (PI), and proportional derivative control (PD), or a combination thereof, a proportional integral derivative control (PID control), may be used to control the various components.

As illustrated in FIG. 2, the controller 96 may be provided with a memory 100 and a central processing unit (CPU) 102. The memory 100 may be used for storing the control software that is executed by the CPU 102 in completing a cycle of operation using the washing machine 10 and any additional software. Examples, without limitation, of cycles of operation include: wash, heavy duty wash, delicate wash, quick wash, pre-wash, refresh, rinse only, and timed wash. The memory 100 may also be used to store information, such as a database or table, and to store data received from one or more components of the washing machine 10 that may be communicably coupled with the controller 96. For example, the memory 100 may be used to store a plurality of drum acceleration ramp profiles for respective ones of a plurality of balancing ring fluid viscosities. The database or table may also be used to store the various operating parameters for the one or more cycles of operation, including factory default values for the operating parameters and any adjustments to them by the control system or by user input.

The controller 96 may be operably coupled with one or more components of the washing machine 10 for communicating with and controlling the operation of the component to complete a cycle of operation. For example, the controller 96 may be operably coupled with the motor 88, the pump 74, the dispenser 62, the steam generator 82 and the sump heater 84 to control the operation of these and other components to implement one or more of the cycles of operation.

The controller 96 may also be coupled with one or more sensors 104 provided in one or more of the systems of the washing machine 10 to receive input from the sensors, which are known in the art and not shown for simplicity. Non-limiting examples of sensors 104 that may be communicably coupled with the controller 96 include: a treating chamber temperature sensor, a moisture sensor, a weight sensor, a chemical sensor, a position sensor, a load position sensor, a balancing ring ball position sensor, a motor temperature sensor, and a motor torque sensor, which may be used to determine a variety of system and laundry characteristics, such as balancing ring 38 temperature, balancing ring mass position(s), load position and/or laundry load inertia or mass.

In one example, one or more load amount sensors 106 may also be included in the washing machine 10 and may be positioned in any suitable location for detecting the amount of laundry, either quantitative (inertia, mass, weight, etc.) or qualitative (small, medium, large, etc.) within the treating chamber 18. By way of non-limiting example, it is contemplated that the amount of laundry in the treating chamber may be determined based on the weight of the laundry and/or the volume of laundry in the treating chamber. Thus, the one or more load amount sensors 106 may output a signal indicative of either the weight of the laundry load in the treating chamber 18 or the volume of the laundry load in the treating chamber 18. As used herein, a small load is defined to be an amount of laundry that can be balanced by the moveable mass of the balancing ring 38 without needing to distribute the laundry in the drum 16, taking into consideration the amount of imbalance that can be compensated by the suspension system 28 of the washing machine 10. For example, if the suspension system 28 can accommodate a 1 kilogram (kg) imbalance and the moveable mass of the balancing ring 38 is 0.7 kg, then a small load is an amount of laundry that weighs less than 1.7 kg. In some examples, a small load is a load having a weight or volume equal to or less than a threshold that represents the equivalent of 1 or 2 towels. As used herein, “determining” means any manner, direct or indirect, by any actor, human or machine, by which a parameter or condition may be decided, which includes, without limitation sensing, calculating, estimating, experimenting, empirically, theoretically, mathematically, identifying, detecting, computing, measuring, reading an output of a sensor, and reading a sensor output from a memory.

The one or more load amount sensors 106 may be any suitable type of sensor capable of determining the weight or volume of laundry in the treating chamber 18. Non-limiting examples of load amount sensors 106 for determining the weight of the laundry may include load volume, pressure, or force transducers that may include, for example, load cells and strain gauges. It has been contemplated that the one or more such sensors 106 may be operably coupled to the suspension system 28 to determine the weight borne by the suspension system 28. The weight borne by the suspension system 28 correlates to the weight of the laundry loaded into the treating chamber 18 such that the sensor 106 may indicate the weight of the laundry loaded in the treating chamber 18. In the case of a suitable sensor 106 for determining volume it is contemplated that an IR or optical based sensor may be used to determine the volume of laundry located in the treating chamber 18.

Alternatively, it has been contemplated that the washing machine 10 may have one or more pairs of feet 108 extending from the cabinet 12 and supporting the cabinet 12 on the floor and that a weight sensor (not shown) may be operably coupled to at least one of the feet 108 to sense the weight borne by that foot 108, which correlates to the weight of the laundry loaded into the treating chamber 18. In another example, the amount of laundry within the treating chamber 18 may be determined based on motor sensor output, such as output from a motor torque sensor. The motor torque is a function of the inertia of the rotating drum and laundry. There are many known methods for determining the load inertia, and thus the load mass, based on the motor torque. It will be understood that the details of the load amount sensors are not germane to this disclosure as any suitable method and sensors may be used to determine the amount of laundry.

As described in more detail below, the washing machine 10 may be controlled to substantially balance the drum 16 during high-speed spinning of small loads of laundry to remove fluid from the laundry. In particular, the drum 16 may be accelerated according to a particular ramp profile that results in the moveable mass of the balancing ring 38 being substantially opposite a small load when the drum 16 rotates at or through its critical rotation speed(s). As used herein, a critical rotation speed of the drum 16 corresponds to the natural resonant frequency of the suspension system 28, that is, the rotation speed of the drum 16 at which an imbalance of the drum 16 is likely to result in substantial, significant and/or unacceptable movement of the drum 16. In general, the suspension critical frequencies depend on the mass of the suspended assembly and the characteristics of the suspension system 28. The suspended assembly may have more than one natural frequency corresponding to side-to-side, up-down, and front-to-back movement of the drum 16. Example critical speeds for a horizontal-axis washing machine are 70-180 revolutions-per-minute (rpm) side-to-side, 160-250 rpm up-down, and 70-140 rpm front-to-back.

Referring now to FIG. 3, a flow chart of a method for controlling the acceleration of the drum 16 to balance a small load is illustrated. The sequence of operations depicted for this method and the proceeding methods are for illustrative purposes only, and is not meant to limit any of the methods in any way as it is understood that the operations may proceed in a different logical order or additional or intervening operations may be included.

The method of FIG. 3 starts with assuming that a user has placed one or more laundry articles for treatment within the treating chamber 18 and selected a cycle of operation through the user interface 98. The method may be implemented during any portion of a cycle of operation or may be implemented as a separate cycle of operation. For example, the method may be implemented during a rinse-and-spin cycle and/or a final-spin cycle. The controller 96 determines whether a small load is present in the drum 16 (block 305). For example, the controller 96 may automatically determine when a small load is present in the drum 16 using outputs of one or more sensors 104. Alternatively, the user may select a cycle and/or option that corresponds to a small load.

If a small load is present in the drum 16 (block 305), the controller 96 positions the drum 16 such that the small load is positioned at the bottom of the drum 16 (block 310). The controller 96 determines the temperature of the fluid in the balancing ring 38 using, for example, any or all of the example methods of FIGS. 4-6 (block 315). Alternatively, the temperature of the fluid in the balancing ring 38 may be directly measured. Based on the determined temperature, the controller 96 estimates the viscosity of the fluid in the balancing ring 38 (block 320). In some examples, a table lookup is performed based on the determine temperature to obtain the viscosity. In other examples, a mathematical function is used to determine the viscosity given the temperature.

Based on the determined viscosity, the controller 96 selects a drum acceleration ramp profile (block 325). In some examples, the controller 96 selects the drum acceleration ramp profile from a table of ramp profiles according to the viscosity. That is, the memory 100 may store a plurality of ramp profiles for respective ones of a plurality of fluid viscosities. In some examples, the plurality of ramp profiles are determined empirically based on laboratory experiments. In other examples, the plurality of ramp profiles are mathematically derived based on the theoretical movement of the moveable mass in the viscous fluid. Example ramp profiles for a plurality of viscosities are illustrated in FIGS. 7A and 7B. As shown in FIG. 7A, a ramp profile may include a dwell time, that is, a period of time where the rotation speed is held substantially constant. Because the fluid viscosity and the fluid temperature are related, the ramp profile may alternatively be selected based on the estimated fluid temperature without estimating the fluid viscosity.

Returning to FIG. 3, the controller 96 waits an amount of time to allow the moveable mass of the balancing ring 38 to settle to the bottom of the balancing ring 38, as shown in FIG. 8 (block 330). In some examples, the amount of time is a fixed predetermined amount of time. In other examples, the amount of time is adjusted based on the determined viscosity. The controller 96 accelerates the rotation of the drum 16 according to the selected ramp profile (block 335). As the drum 16 accelerates, the moveable mass of the balancing ring 38 gradually moves to a position opposite the small load. When the speed of rotation of the drum 16 is at or passes through the critical speed(s), the moveable mass of the balancing ring 38 will be positioned substantially opposite the small load, as shown in FIG. 9. For example, the moveable mass may become positioned opposite the small load at a rotation speed slower than the critical frequency(-ies) and then be maintained substantially opposite the small load by centrifugal force as the drum accelerates through the critical speed(s). Alternatively, the moveable mass may become positioned opposite the small load at or beyond the critical frequency(-ies). To the extent that the moveable mass is not positioned opposite the small load at the critical frequency(-ies), the size of the small load that can be balanced may be diminished. At high frequencies (e.g., beyond the critical speed), centrifugal force will maintain the moveable mass of the balancing ring 38 substantially opposite the small load, thus, maintaining the balanced state. Control then exits from the example method of FIG. 3.

Returning to block 305, if a small load is not detected or indicated (block 305), the controller 96 performs normal drum acceleration (block 340) and control exits from the example method of FIG. 3.

Alternatively, rather than initially aligning the moveable mass of the balancing ring 38 and the small load, the position(s) of the moveable mass (e.g., balls) of the balancing ring 38 and the small load may be determined. Then a ramp profile may be selected based on the fluid viscosity and the difference in position between the small load and the moveable mass, thus, obviating the need to wait for the small load and the moveable mass to become substantially aligned.

FIGS. 4-6 are flowchart representative of example methods that may be used to implement block 315 of FIG. 3. Any one or any combination of the methods of FIGS. 4-6 may be used to determine the temperature of the fluid in the balancing ring 38. The method of FIG. 4 begins with the controller 96 determining the temperature of a fluid in the drum 16 using, for example, one of the sensors 104 (block 405). The controller 96 determines the temperature and/or viscosity of the fluid in the balancing ring 38 based on the temperature of the fluid in the drum 16 (block 410). Control then exits from the example method of FIG. 4. Alternatively, an ambient temperature may be determined and used to determine the temperature of the fluid in the balancing ring 38.

The method of FIG. 5 begins with the controller 96 determining the temperature of the motor 88 using, for example, one of the sensors 104 (block 505). The controller 96 determines the temperature and/or viscosity of the fluid in the balancing ring 38 based on the temperature of the motor 88 (block 510). Control then exits from the example method of FIG. 5.

The method of FIG. 6 begins with the controller 96 determining information representing the mechanical and/or electrical energy put into the washing machine 10 during a predetermined period of time (block 605). For example, the controller 96 may determine length of wash cycle, heater usage, rotations of the drum 16, etc. within a given time period. Based on the mechanical and/or electrical energy put into the washing machine 10 and optionally the time period, the controller 96 determines the mechanical energy put in the moveable mass (e.g., ball and fluid) of the balancing ring 38 due to motion of the moveable mass (block 610). In some examples, a table lookup is performed to determine the energy put into the moveable mass based on the mechanical and/or electrical input energy. The table may, for example, be determined using empirical laboratory measurements. The controller obtains the electrical energy input to the heater and/or steamer (block 615). Based on the mechanical energy put into the moveable mass and the electrical energy, the controller 96 determines the temperature and/or viscosity of the fluid in the balancing ring 38 (block 620). In some examples, a table lookup is performed to determine the fluid temperature and/or viscosity from the energy(-ies) put into the moveable mass. The table may, for example, be determined using empirical laboratory measurements. Control then exits from the example method of FIG. 6.

A processor, a controller and/or any other suitable processing device such as the example CPU 102 may be used, configured and/or programmed to execute and/or carry out the example methods of FIGS. 3-6. For example, the methods of FIGS. 3-6 may be embodied in program code and/or machine-readable instructions stored on a tangible computer-readable medium such as the memory 100. Many other methods of implementing the methods of FIGS. 3-6 may be employed. For example, the order of execution may be changed, and/or one or more of the blocks and/or interactions described may be changed, eliminated, sub-divided, or combined. Additionally, any or all of the methods of FIGS. 3-6 may be carried out sequentially and/or carried out in parallel by, for example, separate processing threads, processors, devices, discrete logic, circuits, etc.

As used herein, the term “tangible computer-readable medium” is expressly defined to include any type of computer-readable medium and to expressly exclude propagating signals. As used herein, the term “non-transitory computer-readable medium” is expressly defined to include any type of computer-readable medium and to exclude propagating signals. Example tangible and/or non-transitory computer-readable medium include a volatile and/or non-volatile memory, a volatile and/or non-volatile memory device, a flash memory, a read-only memory (ROM), a random-access memory (RAM), a programmable ROM (PROM), an electronically-programmable ROM (EPROM), and/or an electronically-erasable PROM (EEPROM).

To the extent not already described, the different features and structures of the various embodiments may be used in combination with each other as desired. That one feature may not be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments may be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described.

Although certain example methods, apparatus and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the claims of this patent. 

What is claimed is:
 1. A method of operating a laundry treating appliance having a rotating drum defining a treating chamber in which laundry is received for treatment according to at least one cycle of operation, and a balancing ring to counteract an imbalance of the rotating drum, the method comprising: determining whether a small load is present in the treating chamber; substantially aligning the small load and a moveable mass of the balancing ring when the drum is substantially stationary; and accelerating rotation of the drum based on a viscosity of fluid in the balancing ring to position the small load substantially opposite the moveable mass.
 2. A method as defined in claim 1, wherein the moveable mass comprises the fluid.
 3. A method as defined in claim 1, wherein the drum is accelerated such that the small load and the moveable mass are substantially opposite at and above a critical rotation speed of the drum.
 4. A method as defined in claim 3, wherein the critical rotation speed corresponds to a natural resonant frequency of a suspension system.
 5. A method as defined in claim 3, wherein the critical rotation speed is between about 70 to 250 revolutions-per-minute.
 6. A method as defined in claim 1, further comprising: determining a temperature of the fluid; and determining the viscosity of the fluid based on the determined temperature.
 7. A method as defined in claim 6, wherein determining the temperature of the fluid comprises measuring the temperature of the fluid.
 8. A method as defined in claim 6, further comprising determining a temperature of a second fluid in the drum, wherein the temperature of the fluid in the balancing ring is determined based on the determined temperature of the second fluid.
 9. A method as defined in claim 6, further comprising determining a motor temperature, wherein the temperature of the fluid in the balancing ring is determined based on the determined motor temperature.
 10. A method as defined in claim 6, further comprising determining an ambient temperature, wherein the temperature of the fluid in the balancing ring is determined based on the determined ambient temperature.
 11. A method as defined in claim 1, further comprising determining an energy input to the balance ring over a predetermined time period, wherein the viscosity of the fluid is determined based on the estimated energy.
 12. A method as defined in claim 11, further comprising determining the energy input based on a number of cycles operated over a given period of time.
 13. A method as defined in claim 11, further comprising determining at least one of a mechanical or an electrical energy input into the laundry treating appliance, wherein the energy input to the balance ring is determined based on the at least one of the mechanical or the electrical energy input into the laundry treating appliance.
 14. A method as defined in claim 1, further comprising accelerating rotation of the drum according to a ramp profile selected from a plurality of ramp profiles based on the estimated viscosity of the fluid.
 15. A method as defined in claim 14, wherein the plurality of ramp profiles correspond to respective ones of a plurality of viscosities.
 16. A method as defined in claim 1, further comprising: stopping a rotation of the drum; and holding the drum substantially stationary to allow the moveable mass and the small load to substantially align.
 17. A method as defined in claim 1, wherein determining whether the small load is present comprises comparing at least one of a weight or a volume of the small load to a threshold.
 18. A method as defined in claim 1, wherein determining whether the small load is present comprises receiving a user input.
 19. A method of operating a laundry treating appliance having a rotating drum defining a treating chamber in which laundry is received for treatment according to at least one cycle of operation, and a balancing ring to counteract an imbalance of the rotating drum, the method comprising: determining a position of a moveable mass of the balancing ring; and accelerating rotation of the drum based on a viscosity of fluid in the balancing ring, a location of a small load in the treating chamber, and the detected position to position the small load substantially opposite the moveable mass at and above a critical rotation speed of the drum.
 20. A method as defined in claim 19, further comprising determining the location of the small load in the treating chamber;
 21. A method as defined in claim 19, further comprising: determining a temperature of the fluid; and determining the viscosity of the fluid based on the determined temperature.
 22. A method as defined in claim 19, further comprising accelerating the rotation of the drum according to a ramp profile selected from a plurality of ramp profiles based on the viscosity of the fluid.
 23. A method as defined in claim 22, wherein the plurality of ramp profiles correspond to respective ones of a plurality of viscosities.
 24. A laundry treating appliance comprising: a rotating drum defining a treating chamber in which laundry is received for treatment according to at least one cycle of operation; a balancing ring coupled with the rotating drum to counteract an imbalance of the rotating drum; a controller configured to determine whether a small load is present in the treating chamber, substantially align the small load and a moveable mass of the balancing ring when the rotating drum is substantially stationary, and accelerate rotation of the drum based on an estimated temperature of fluid in the balancing ring to position the small load substantially opposite the moveable mass at and above a critical rotation speed of the drum.
 25. A laundry treating appliance as defined in claim 24, further comprising a sensor to determine a presence of the small load in the treating chamber.
 26. A laundry treating appliance as defined in claim 24, wherein the controller is to determine whether the small load is present in the treating chamber based on a user input.
 27. A laundry treating appliance as defined in claim 24, wherein the critical rotation speed corresponds to a natural resonant frequency of a suspension system as the drum is rotated.
 28. A laundry treating appliance as defined in claim 24, wherein the controller is to: determine the temperature of the fluid; and select a ramp profile from a plurality of ramp profiles based on the determined temperature; and accelerate rotation of the drum according to the ramp profile. 